A method for secure single-channel transmission of data between the computer nodes (RK1, RK2) of a computer network a) a failsafe executed computer node (RK1), the at least two operating in parallel, connected by a node internal communication channel with each other computers (R1A, R1B, R1C) which via a node external communication channel (KAN) to another such computer node (RK2) user data and determined from the user data and these locking in the transmission data redundancy sends, characterized, b) that the determination of the correct redundancy data to user data, which transmits a computer (R1A) via the node external communication channel, exclusively in a computer (R1B, R1C) is carried out or by sequential calculation, wherein said redundancy data in a computer (R1A) exclusively from determined in a different computer (R1B, R1C) partial result are determined, wherein c) the redundancy data are determined from the useful data using a table, in which each computer in a data memory under specified addresses ...